The present invention relates to the treatment oftextiles, and more particularly to fabrics having water repellant, stain resistant, and wrinkle-free properties and methods of producing same. Most particularly, the present invention relates to producing water repellant, stain resistant, and wrinkle-free fabrics which display excellent hand and feel.
U.S. Pat. No. 5,856,245 discloses an example of a barrier web comprising a fabric that has been treated with a curable shear thinned thixotropic polymer composition, the fabric being substantially impermeable to liquids, permeable to gases and impermeable to all microorganisms.
U.S. Pat. No. 5,869,172 discloses an example of processes for treating a porous substrate which involves controlled placement of modifiers through the manipulation of chemical and physical properties inherent in the modifiers to produce internally coated porous materials. The treatment involves impregnating the porous substrate with a curable thixotropic material and one or more modifying materials to impart desired properties.
U.S. Pat. Nos. 5,874,164 and 5,912,116 provide examples of a barrier web comprising a fabric that has been treated with a curable shear thinned thixotropic polymer composition. The fabric is substantially impermeable to liquids, permeable to gases and impermeable to all microorganisms. The barrier webs are either impermeable to all microorganisms or are impermeable to microorganisms of certain sizes. These patents also disclose fabrics that are capable of selectively binding certain microorganisms, particles or molecules depending upon the binding agents incorporated into the polymer before application to the fabric.
The present invention is directed to a textile treatment process that imparts water repellant, stain resistant, and wrinkle-free properties as well as aesthetically pleasing hand properties to a fabric made in whole or in part of fibers having a hydroxyl group, such as cellulosic fibers. The present invention is also directed to the resultant fabric of the process.
The fabrics are treated by immersion into an aqueous bath thereby applying a controlled amount of the bath to the fabric. The fabrics are then preferably dried to their natural regain, and pressed to remove unwanted wrinkles. Thereafter heat is applied to cure the reactants.
The aqueous bath is preferably formulated to apply to the fabric 8% to 14% by weight of the fabric of a reactive modified ethylene urea resin solution and 4% to 10% by weight of a crosslinking polytetrafluorethylene additive which is at least 25% by weight polytetrafluorethylene. Upon immersion of a fabric which has fibers having a hydroxyl group, such as cellulosic fibers, and subsequent heating, the urea resin reacts with the hydroxyl group and forms crosslinks with the polytetrafluorethylene to impart the desired properties to the fabric.
Alternatively, the bath is formulated to apply 0.6% to 3.3% by weight of the fabric of a urea resin, preferably DMDHEU, 0.3% to 1.5% polytetrafluorethylene (PTFE), and 1 to 4% fluoroalkyl acrylate co-polymer. A bonding reaction between the urea resin and the hydroxyl group on the fabric is initiated upon immersion of the fabric and strengthened when heat is applied during the drying and curing processes.
Preferably, the bath contains a buffer to maintain pH in a range of 3.5 to 5.5 and a catalyst to speed the reaction.
Objects and advantages of the present invention will become more readily apparent to those skilled in the art upon consideration of the following detailed description which describes a preferred embodiment of the invention.